There have been generally known three kinds of methods for obtaining an ontically active compound by chemical synthesis: optical resolution methods, induction methods and asymmetric synthesis methods.
However, there are problems in that 1) induction methods do not allow much choice in the starting substance, 2) asymmetric synthesis methods allow only a limited number of reactions to afford the objective substance at a high optical purity, and 3) from among the optical resolution methods, a method for resolution by high performance liquid chromatography (HPLC) using a chiral column is not an economical synthetic method suitable for mass synthesis.
Accordingly, a production method of an optically active compound, which is convenient and suitable for mass synthesis, is desired.
The present inventors have conducted various studies and, as a result, found a method for economically and conveniently producing an optically active form having a sulfonamide group, which comprises reaction of a racemate of sulfonamide having an asymmetric carbon with an optically active carboxylic acid to derive a diastereomeric form of acyl sulfonamide, optical resolution thereof to give an intermediate, and hydrolysis of the intermediate, which resulted in the completion of the present invention.